Vehicle ignition system using ignition module with reduced heat generation

ABSTRACT

An ignition system for a vehicle includes a distributor having with a Hall Effect stator assembly and ignition module formed preferably as a thick film integrated (TFI) module, which receives a spark output (SPOUT) signal from an electronic control assembly (ECA). The ignition module includes a microprocessor for generating a control signal to an ignition coil and switching ON and OFF the primary current therein. A temperature sensing circuit is operative with the microprocessor for reducing the duty cycle or overall current or power as applied to the control signal from the TFI ignition module to the ignition coil and reducing the heat generated by the TFI ignition module when a temperature threshold for the TFI ignition module has been exceeded.

FIELD OF THE INVENTION

[0001] This invention relates to the field of ignition systems forvehicles, and more particularly, this invention relates to ignitionsystems for vehicles using an electronic control assembly (ECA), adistributor, and ignition module that switches ON and OFF the primarycurrent to the ignition coil.

BACKGROUND OF THE INVENTION

[0002] Electrical ignition systems are used in most automotive vehiclesto create a high-voltage current (about 20,000 to about 40,000 volts ormore) to a sparkplug and create an arc across the gap at the base of thesparkplug. This high-voltage current creates a strong spark that ignitesthe air/fuel mixture for combustion. The ignition system also controlsthe spark timing such that the spark occurs at the right time and in thecorrect cylinder. Although many different automotive ignition systemshave developed over the last century, most ignition systems only differin the method or system used to create the spark.

[0003] In the original electrical ignition systems, a mechanical systemused simple breaker points as a switching mechanism to control a currentflow through an ignition coil containing the primary and secondarywinding circuits. Usually the primary winding of the ignition coilcontains about 100 to about 150 turns of heavy and insulated copperwire. The insulation insulates the turns and prevents electrical shorts.A secondary coil winding contains about 15,000 to about 30,000 or moreturns of fine copper wire, also insulated, and typically wound around asoft iron core. Usually oil is used for cooling the coil and it providesa medium to protect the coil from the excessive heat generated by largecurrent flows. Other cooling mechanisms can also be used. As currentflows through the primary coil, a magnetic field is established. Whenthe breaker points are opened, the current is shut off and thecollapsing magnetic field induces a high voltage in the secondarywinding that is released through a center coil tower to a rotor, whichdistributes spark through a distributor cap and high tension sparkplugwires to the proper sparkplug.

[0004] Automotive electrical ignition systems have advanced over theyears from simple vacuum advance mechanical systems to electronicsystems. Modern ignition systems use distributorless (electronic)ignition systems (EIS) that replace prior mechanical and simpleelectronic ignition systems with computer-controlled spark advance. In adistributorless ignition system(DIS), a crankshaft timing sensortriggers the ignition system, which typically includes a Hall Effectmagnetic switch activated by vanes on a crankshaft damper and pulleyassembly. A signal is generated corresponding to vehicle engine timingand RPM and transmitted to the distributorless ignition system (DIS) anda microprocessor that is part of a distributorless ignition system (DIS)electronic control assembly or module. A camshaft sensor can provideinformation on cylinder position for the ignition coil and fuel system.The distributorless ignition system (DIS) electronic engine assemblyreceives a signal from the crankshaft sensor and camshaft sensor and aspark signal from a computer of the vehicle to control the ignitioncoils, allowing them to fire in the correct sequence. The DIS electroniccontrol assembly can also control engine dwell. An ignition coil packcan use multiple ignition coils and the DIS electronic control assemblycontrols the coils.

[0005] The DIS ignition system and similar circuit components arecommonly used on most modern automotive vehicles. Millions of earlierdesigned electronic ignition systems (EIS), however, are still used onearlier vehicle models and are still operable, although many are nowfailing. These earlier electronic ignition systems still use acomputer-controlled spark advance system and ignition coil having theprimary and secondary windings. An electronic control assembly (ECA)receives many sensor inputs and generates a spark output (SPOUT) signal.The distributor has a typical multipoint or similarly designed rotor orarmature, shaft assembly and a Hall Effect stator assembly mounted inthe distributor that generates a profile ignition pickup (PIP) signal tothe electronic control assembly (ECA) indicative of crankshaft positionand engine RPM. An ignition module is formed as a thick film integrated(TFI) module and has an integrated circuit within a module housing thatis usually mounted on the distributor base. It receives the spark output(SPOUT) signal from the electronic control assembly (ECA). The TFImodule generates a control signal to the ignition coil and switches ONand OFF the primary current therein, typically using an insulated gatefield effect transistor (IGFET) or similar switching device.

[0006] A major drawback of these prior art thick film integrated (TFI)modules and similar ignition modules is the excessive production ofgenerated heat resulting from the large duty cycle and constant ONoperation when the TFI module generates signals to the ignition coil tofire the spark at proper timing intervals. Although the TFI moduleusually includes a heat sink to aid in absorbing excessive amounts ofgenerated heat at low idle speeds and other automotive operationsconditions, excessive heat is still generated, at the TFI module andignition coil, possibly resulting in logic errors, signal transmissionerrors, and other automotive problems.

SUMMARY OF THE INVENTION

[0007] It is therefore an object of the present invention to provide anignition system for vehicles having an ignition coil, electronic controlassembly (ECA) and ignition module, such as a thick film integrated(TFI) module, and having reduced heat generation, especially at idle andlow RPM speeds.

[0008] The present invention advantageously incorporates amicroprocessor within the ignition module for generating a controlsignal to an ignition coil and switching ON and OFF the primary currenttherein. A temperature sensing circuit is operative with themicroprocessor such that the duty cycle or overall output current asapplied to the control signal from the ignition module to the ignitioncoil is reduced for reducing the heat when a temperature threshold forthe ignition module has been exceeded.

[0009] In accordance with the present invention, an ignition system fora vehicle includes an ignition coil having primary and secondarywindings for generating high-voltage signals to sparkplugs. Anelectronic control assembly (ECA) generates a spark output (SPOUT)signal. A distributor includes a Hall Effect stator assembly mountedtherein that generates a profile ignition pickup (PIP) signal indicativeof crankshaft position and engine RPM to the electronic control assembly(ECA). The ignition module as a preferred thick film integrated (TFI)module receives the spark output (SPOUT) signal from the electroniccontrol assembly (ECA). The ignition module includes a microprocessorfor generating a control signal to an ignition coil and switching ON andOFF the primary current therein. A temperature sensing circuit isoperative with the microprocessor for reducing the duty cycle or overalloutput current or power as applied to the control signal from theignition module to reduce the generated heat when a temperaturethreshold for the ignition module has been exceeded.

[0010] In yet another aspect of the present invention, the distributorbase has mounted therein an armature and shaft assembly. The ignitionmodule is mounted on the distributor. A thick film substrate in themodule comprises an integrated circuit and includes a microprocessorthat is operative for reducing the duty cycle or overall or averageoutput current or power from about 5% to about 15%. A temperaturesensing circuit typically includes a temperature sensing resistor andreference diode. The ignition module also includes a voltage reductioncircuit for reducing vehicle voltage from the normally 14 or 15 volts toabout 5 volts for supplying power to the microprocessor. The ignitionmodule also includes a signal input for receiving a profile ignitionpickup (PIP) signal from the Hall Effect stator assembly. Themicroprocessor is operative for comparing the spark output (SPOUT)signal with the profile ignition pickup (PIP) signal to determine atiming interval for switching ON and OFF the primary current within theignition coil. The microprocessor can also be operative for determiningwhen an engine threshold has been exceeded by processing engineoperating parameters as determined by at least the spark output (SPOUT)signal and/or profile ignition pickup (PIP) signals generated to theignition module. The microprocessor can also be operative for reducingthe duty cycle or overall current or power after the temperature hasbeen exceeded and when the engine RPM of the vehicle has dropped below apredetermined number.

[0011] In accordance with the present invention, a distributor for thevehicle includes a distributor base having a Hall Effect stator assemblymounted therein that generates a profile ignition pickup (PIP) signalindicative of crankshaft position and engine RPM to an electroniccontrol assembly (ECA) used on the vehicle. The ignition module receivesa spark output (SPOUT) signal from an electronic control assembly (ECA)used on the vehicle. The ignition module includes a microprocessor forgenerating a control signal to an ignition coil and switching ON and OFFthe primary current therein. A temperature sensing circuit is operativewith the microprocessor for reducing the duty cycle or overall currentor power as applied to the control signal from the ignition module tothe ignition coil and reducing the generated heat when a temperaturethreshold for the ignition module has been exceeded.

[0012] In accordance with another aspect of the present invention, theignition module is formed as a thick film integrated (TFI) module. Itincludes a housing adapted for mounting on a distributor. A thick filmsubstrate is contained within the housing. A microprocessor is mountedon the thick film substrate and is operative for receiving at least aspark output (SPOUT) signal from an electronic control assembly (ECA)used on the vehicle. The TFI module generates a control signal to anignition coil and switching ON and OFF the primary current therein. Atemperature sensing circuit is operative with the microprocessor forreducing the duty cycle or overall current or power as applied to thecontrol signal generated to the ignition coil to reduce the generatedheat when a temperature threshold for the TFI module has been exceeded.

[0013] A method is also disclosed for operating an ignition system of avehicle having an electronic engine control (EEC). The method includesthe step of monitoring the temperature of an ignition module, such as athick film integrated (TFI) module, which receives a spark output(SPOUT) signal from an electronic control assembly (ECA). A controlsignal is generated to an ignition coil for switching ON and OFF theprimary current therein. The method further comprises the step ofreducing the duty cycle or overall current or power as applied to thecontrol signal from the ignition module to the ignition coil andreducing the generated heat when a temperature threshold for theignition module has been exceeded. The method can also include the stepsof monitoring the temperature in an ignition module mounted on adistributor having a Hall Effect stator assembly that generates aprofile ignition pickup (PIP) signal indicative of crankshaft positionand engine RPM to an electronic control assembly (ECA), which produces aspark output (SPOUT) signal to the ignition module. The ignition moduleincludes a microprocessor operative for reducing the duty cycle asapplied to control signals to the distributor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other objects, features and advantages of the present inventionwill become apparent from the detailed description of the inventionwhich follows, when considered in light of the accompanying drawings inwhich:

[0015]FIG. 1 is a block diagram of a typical thick film integrated (TFI)ignition system using an electronic control assembly (ECA) distributorwith Hall Effect stator assembly and thick film integrated (TFI) modulemounted on the distributor.

[0016]FIG. 2 is a block diagram showing the basic signals passingbetween the TFI module and the electronic control assembly.

[0017]FIG. 3 is another block diagram showing various signals that passto and from the TFI module and showing ignition advance relative to theprofile ignition pickup (PIP) and spark output (SPOUT) signals.

[0018]FIG. 4 is a schematic circuit diagram of one example of a circuitused for the thick film integrated (TFI) module in accordance with thepresent invention, and including a microprocessor and temperaturesensing circuit operative with the microprocessor for reducing dutycycle or overall current or power as applied to the control signal fromthe TFI module to the ignition coil and reducing generated heat when atemperature threshold for the TFI module has been exceeded.

[0019]FIG. 5 is another schematic circuit diagram similar to that shownin FIG. 4, but using an 8-pin microprocessor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The present invention will now be described more fullyhereinafter with reference to the accompanying drawings, in whichpreferred embodiments of the invention are shown. This invention may,however, be embodied in many different forms and should not be construedas limited to the embodiments set forth herein. Rather, theseembodiments are provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like numbers refer to like elements throughout.

[0021] The present invention advantageously provides an ignition systemfor a vehicle of the type having an ignition coil with primary andsecondary windings for generating high-voltage signals to sparkplugswhere an ignition module as a preferred thick film integrated (TFI)module has reduced heat generation, such as when operating at a lowengine RPM, thus reducing the overall heat generated at the TFI module.In this ignition system, an electronic control assembly (ECA) generatesa spark output (SPOUT) signal as known to those skilled in the art. Thedistributor includes a Hall Effect stator assembly mounted therein thatgenerates a profile ignition pickup (PIP) signal indicative ofcrankshaft position and typically engine RPM to the electronic controlassembly (ECA).

[0022] A thick film integrated (TFI) module receives a spark output(SPOUT) signal from the electronic control assembly (ECA). In accordancewith the present invention, the TFI module includes a microprocessorthat is programmed for the engine (such as four, six, eight cylinderengines) and generating a control signal to the ignition coil andswitching ON and OFF the primary current therein. A temperature sensingcircuit is operative with the microprocessor and operative for reducingthe duty cycle or overall current or power as applied to the controlsignal from the TFI module to the ignition coil and reducing thegenerated heat when a temperature threshold for the TFI module has beenexceeded. The present invention is especially applicable when the engineRPM is low, such as at idle speeds and below, and other low-speed engineoperation where the amount of heat generation can be excessive.

[0023] Referring now to FIG. 1, there is illustrated a block diagram ofa typical thick film integrated (TFI)(type IV) electronic ignitionsystem (EIS) 10, as one non-limiting example, used on thousands ofdifferent vehicles still in existence at the present time. A battery 12provides the starting current and power at around 14 to about 15 voltsto a starter relay 14. An ON/OFF/Start (ignition) switch 16 isoperatively connected to an “E”-core ignition coil 18, which in turn, isoperatively connected to a distributor assembly 20 via a distributor cap22. The sparkplugs 24 receive high-voltage current via high tensionsparkplug wires 25 as illustrated. The distributor assembly 20 includesa multi-point rotor 30 and an ignition module, which in the illustratedembodiment is a non-limiting thick film integrated (TFI) module 32. TheTFI module 32 is mounted on a distributor base 34. The TFI moduleincludes a module housing with a substrate therein and having lead wires35 to the ignition coil 18 and an electronic control assembly (ECA) 36.The substrate can be adapted for surface mount technology. Thedistributor assembly 20 usually includes an armature 20 a and shaftassembly 20 b mounted in the distributor base 34 with possibly theaddition of appropriate washers, snap rings, octane rods, grommets,bases, o-rings and drive gears as known to those skilled in the art.

[0024] Although the block diagram of FIG. 1 shows only one type ofinterconnection among the different ignition circuit elements, it shouldbe understood that different ignition circuit elements can be connectedin different combinations as suggested to those skilled in the art. Thepresent invention is not necessarily limited to the illustratedcomponents. This type of electronic ignition system 10 typically doesnot use centrifugal or vacuum advance mechanisms, but instead uses aHall Effect stator assembly 38 (also known as the stator) that generatesa profile ignition pickup (PIP) signal to the electronic controlassembly 36. The profile ignition pickup (PIP) signal is processed bythe electronic control assembly 36 and produces a spark output (SPOUT)signal that is transferred to the TFI module 32. ON and OFF current isswitched by the TFI module 32 in the primary winding of the ignitioncoil 18. The interruption of the primary current in the ignition coilcauses an open circuit, such that the collapsing magnetic field on thesecondary coil produces a high voltage from about 20,000 to about 40,000volts or higher. The high-voltage pulses are sent to the distributor 20,and its rotor 30 and distributor cap 22, which transfers the highervoltage to the sparkplugs using the high tension sparkplug wires forfiring the sparkplugs.

[0025] As shown in the block diagram of FIG. 2, the profile ignitionpickup (PIP) signal is one of the many inputs to the electronic controlassembly 36. All sensor data and information provided by the differentsensor inputs are used to create the spark output (SPOUT) signal thatsignifies electronically the engine operating condition. This signal isforwarded back to the TFI module 32, which is operative and similar toan internal electronic switch. The profile ignition pickup (PIP) signalis generated by the Hall Effect stator assembly and is indicative ofcrankshaft position and typically engine RPM. The TFI module 32 usuallyuses both of these signals for comparison and fires the ignition coil atproper timing intervals.

[0026]FIG. 3 illustrates another block diagram of a TFI module 32 andshows the connectors 34, 36 for connecting to wires and receiving PIPand SPOUT signals that are input into the TFI module. A groundconnection 38 can be connected to an insulated gate bipolar transistor(IGBT) as part of the TFI module 32. Positive and negative coil wires40, 42 are connected to the ignition coil. A start signal is receivedfrom the ignition switch 16 and connects to positive battery voltage.The module 32 also includes a TFI ground point connection 44. The TFImodule also provides a Hall supply voltage to the Hall Effect statorassembly via the Hall supply connection 45.

[0027] If the TFI module has power, is grounded, and receives a profileignition pickup (PIP) signal from the Hall Effect stator assembly, thereshould be spark generation. The electronic control assembly (ECA) 36usually would not control spark until engine RPM is above about 350 RPM.Even when the spark output (SPOUT) signal is eliminated from the overallelectronic engine control, such as by failure, a spark for firing theplug would still occur, but the electronic engine control and moreparticularly, the electronic control assembly would log a fault code.Some TFI modules 32 used on manual transmission vehicles could have a“push start” feature allowing the vehicle to be “push started”. It isalso possible to have a fixed octane adjustment mechanism, such as acontrol rod operative with a distributor advancing mechanism as known tothose skilled in the art.

[0028] As noted before, the profile ignition pickup (PIP) signal isgenerated by the Hall Effect stator assembly 38 to indicate crankshaftposition and engine RPM. This PIP signal is fed to both the TFI module32 and the electronic control assembly 36. The Hall Effect statorassembly 38 is usually formed as part of a rotary vane cup in adistributor and receives the battery voltage and includes a signalreturned through a processor. The Hall Effect stator assembly mayinclude a voltage regulator, a Hall voltage generator, a Darlingtonamplifier, Schmidt trigger and an open collector output stage integratedin a single monolithic silicon chip as part of a pickup assembly. Asignal is produced when a ferrous material passes through an opening andany flux lines decrease. A Darlington amplifier receives a sine wavesignal that is generated by the Hall generator as part of the HallEffect and stator assembly. This signal is inverted by the Darlingtonamplifier, thus creating a high output when the signal is low, and a lowoutput signal when the signal is high. A Schmidt trigger forms a squarewave as a digital “high” signal to another switching transistor that isoperatively connected to ground and in a loop back to the Hall voltagegenerator and regulator.

[0029] The Hall Effect stator assembly can also include a Hall elementwith leads which are spaced from a concentrator with a permanent magnet.An output to the Darlington amplifier is high when a formed window onthe armature allows the magnetic field to reach the Hall device. Thiscorresponds to a switched ON condition. A signal is low to theDarlington amplifier in a switched OFF condition when a tab shunts themagnetic field away from the Hall device. Thus, any windows or openingsin a gap between the Hall device and permanent magnet completes amagnetic path from the magnet, through the Hall device and back to themagnet. Thus, the Hall Effect stator assembly does not transmit asignal. When a tab enters the gap as known to those skilled in the art,an armature cuts the magnetic path and voltage drops. The switch isoperative and signal is sent and switched ON and OFF as the armaturerotates, opening and closing the magnetic path. This signal can be usedby the electronic control assembly to determine the position of thecrankshaft and the engine RPM and used by the TFI module to ensureengine operation when any SPOUT signal is terminated through error ordamage.

[0030] It is also known to have electronic engine controls that can usea signature profile ignition pickup signal when one tab is more narrowthan other tabs. This will provide a different signal to fuel injectors,and is useful for sequential electronic fuel injection (SEFI)systemswhere an injector is timed to coincide with the intake valve opening.

[0031] It is also possible to use an ignition diagnostic monitor (IDM)circuit as one of the inputs to the electronic control assembly from anegative terminal of an ignition coil. This can be used as a comparisonreference and enable the electronic control assembly to determinewhether any intermittent faults occur in the ignition primary circuit.When the electronic control assembly receives a profile ignition pickup(PIP) signal and transmits the spark output (SPOUT) signal to the TFImodule, a signal can be observed by the IDM terminal at the electroniccontrol assembly. This can allow greater diagnostic monitoring of theignition coil signal.

[0032] Referring now to FIG. 4, there is illustrated a schematic circuitdiagram of one example of the types of circuit components that can beused in the thick film integrated (TFI) module 50 of the presentinvention. The TFI module 50 includes a module housing 50 a for mountingon a distributor base. The TFI module 50 includes appropriate connectorterminals for all SPOUT, PIP and power connections. Appropriateanalog-to-digital conversion circuits are included as part of themicroprocessor circuit. The TFI module 50 includes a thick filmintegrated circuit substrate 51 having surface mounted thereon amicroprocessor 52, illustrated as a 20-pin, dual in-line package (DIP).Although a 20-pin microprocessor with trade designation MC68HRC908JK1 isillustrated, an 8-pin or other microprocessor could be used as long asthe appropriate inputs, temperature sensing circuit, voltage reductioncircuit and other circuits for providing a control signal to theignition coil with a reduced duty cycle or overall current or power.Other electronic components can be surface mounted thereon. Themicroprocessor receives a spark output (SPOUT) signal and profileignition pickup (PIP) signal. The microprocessor will be programmed foroperation based on vehicle and engine type, such as four, six or eightcylinder engines. In the illustrated embodiment, the microprocessorincludes various signal pins 54 (labeled pins 1-20) and include aninterrupt (IRQ1) pin, voltage and current supply (VSS and VDD) pins,oscillator pins (OSC1 and OSC2/PTA6), various PTD and PTB pins, and anRST pin. The circuit includes a J1 terminal that connects to a batteryB+ power terminal and a J2 terminal that connects to the starter switch16 and/or relay 14 (FIG. 1) depending on the current design chosen bythose skilled in the art.

[0033] The J3 terminal receives a spark output (SPOUT) signal from theelectronic control assembly 26. The J5 terminal receives the profileignition pickup (PIP) signal from the Hall Effect stator assembly 38 andtransfers it into a “Hall Out terminal, J4. A Hall supply terminal, J6,connects to the Hall connection/power. Negative battery voltage (B−) isprovided at terminal J7, which preferably connects to ground asillustrated and connects to the negative connection terminal of theignition coil. The J8 coil terminal connects to the other coilconnection.

[0034] For purposes of description, the overall function of this circuitis first described followed by more-detailed description of circuitcomponents and interconnections. As noted before, an 8-pinmicroprocessor can accomplish the function as described, but would havedifferent circuit connections as would be understood by those skilled inthe art.

[0035] The TFI module 50 generates a control signal to the ignition coiland switches ON and OFF the primary current therein. A temperaturesensing circuit 60 is operative with the microprocessor 52 and reducesthe duty cycle or average or overall current or power as applied to thecontrol signal from the TFI module to the ignition coil and reduces theheat generated by the TFI module when the temperature threshold for theTFI module has been exceeded. The microprocessor 52 is operative in oneaspect of the present invention for reducing the duty cycle from about5% to about 15%. The temperature sensing circuit 60 in the illustratedembodiment as a non-limiting example includes a temperature sensingresistor 62 and a reference diode 64 that is connected in parallel witha capacitor 66 to establish a temperature control signal back to themicroprocessor 52. This signal is preferably linear as temperaturechanges in the thick film integrated (TFI) module.

[0036] As illustrated, a voltage reduction circuit 70 is operativelyconnected to the starter terminal J2 and reduces vehicle voltage fromabout 14 or 15 volts to about 5 volts for supplying the proper voltageto the microprocessor 52. The voltage reduction circuit 70 includes anintegrated circuit 72 as a translator circuit that is operativelyconnected to the starter terminal J2 and Zener diode CR2 in parallelwith capacitor C1 and C5, as illustrated.

[0037] In the present invention, the microprocessor 52 is operative forcomparing the spark output (SPOUT) signal with the profile ignitionpickup (PIP) signal to determine a timing interval for switching ON andOFF the primary current within the ignition coil. The microprocessor 52is also operative for determining when an engine threshold has beenexceeded by processing engine operating parameters as determined by atleast spark output (SPOUT) signals and/or profile ignition pickup (PIP)signals generated to the TFI module. The microprocessor 52 can beoperative for reducing the duty or overall current or power cycle afterthe temperature threshold has been exceeded and when the engine RPM ofthe vehicle has dropped below a predetermined number, such as below idlespeed, which could correspond to about 330 Hz operation, or even valuesas high as 5000 RPM or lower values such as about 1500 to about 2000RPM. Typically, the microprocessor is programmed to cut back at idlespeeds and below. Although the temperature threshold can vary, dependingon circuit conditions, use of any heat sinks in the TFI module andassociated factors, a typical threshold could vary from about 80 degreesto about 90 degrees Centigrade.

[0038] As illustrated, the output from the microprocessor at PTD4 (pin19) passes through a resistor R11 that provides the biased signal to thebase of transistor Q2. The collector output is passed as an input formodule output transistor Q4, which provides the output to the ignitioncoil connected at terminals J7 and J8. Module output transistor Q4 canbe selected from different types of transistors, including in someexamples an insulated gate bipolar transistor. The microprocessor allowsgreater signal control as compared to prior art devices, allowinginexpensive components, as compared to prior art devices, including amodule output transistor Q4. Other resistors as illustrated provideappropriate voltage divider and other circuit resistances as necessaryfor the illustrated circuit operation. Transistor Q3 acts also to aidoperation of module output transistor Q4.

[0039] The Hall supply terminal J6 is operative with the Hall Effectstator assembly for power supply and includes appropriate Zener diodeCR1 and capacitor C4 in a parallel circuit combination that is operativewith resistors R1 and R2. Transistor Q1 is operative for amplifying thereceived SPOUT and PIP signals into the microprocessor at PTD5 (pin 18).Other capacitors and resistors are illustrated connected within thecircuit for complete circuit operation and have values chosen foroptimum circuit operation.

[0040] The temperature sensing circuit 60 establishes the temperaturecontrol signal to the microprocessor and is linear with the temperaturechange in the thick film integrated (TFI) module of the presentinvention. When a predetermined threshold is reached, such as 85 degreesC. as a non-limiting example, the duty cycle or overall power or currentrelative to the control signal to the ignition coil is reduced, forexample, by about 5% to about 15%, and in another example, by about 10%as non-limiting examples, for reducing heat generation at the TFImodule.

[0041] Referring now to FIG. 5, there is illustrated another embodimentof the present invention for the TFI module 50′ that uses an 8-pinmicroprocessor under the trade designation MC68HC908QT2. The samereference numerals as used in FIG. 4 are used in FIG. 5 (with primenotation) relative to the circuit components. The function of thecircuit shown in FIG. 5 is similar to the function of the circuit shownin FIG. 4. The circuit of FIG. 5 also includes the translator circuit70′ and the temperature sensing circuit 60′. The circuit also usestransistors Q1-Q4 as in FIG. 4. The microprocessor 52′ includes eightsignal pins 54′, including a VDD pin 1, OSC pin 2, an OUT pin 3, an RSTpin 4, a VSS pin 8, a PTAO pin 7, a temperature (TEMP) pin 6 that isoperative with the temperature sensing circuit 60′, and a signal-ininterrupt (IRQ/IN) pin 5 that receives the signal from the transistor Q1that is fed by SPOUT and HALL J3 and J4 terminals. The connections J1-J8are similar as in FIG. 4. The translation circuit 70′ includes threecapacitors C1, C2 and C5 as compared to the two capacitors of FIG. 4,i.e., capacitors C1 and C5. The Zener diode CR2 is a 10-volt Zener diodeas in FIG. 4. Other circuit functions operate similarly.

[0042] Although the system and method of the present invention isillustrated for use with an electronic control assembly and TFI module,it should be understood that the microprocessor and associatedtemperature sensing circuit and translator circuit can be used withother automotive devices where the duty cycle is reduced as applied tocontrol signals from a module to the automotive device, such as analternator or the ignition coil as shown in the drawing figures andexplained above. This would reduce the heat generated by the deviceswhen the temperature threshold forward device has been exceeded.

[0043] Many modifications and other embodiments of the invention willcome to the mind of one skilled in the art having the benefit of theteachings presented in the foregoing descriptions and the associateddrawings. Therefore, it is to be understood that the invention is not tobe limited to the specific embodiments disclosed, and that themodifications and embodiments are intended to be included within thescope of the dependent claims.

That which is claimed is:
 1. An ignition system for a vehiclecomprising: an ignition coil having primary and secondary windings forgenerating high voltage signals to spark plugs; an electronic controlassembly (ECA) that generates a spark output (SPOUT) signal; adistributor having a Hall Effect stator assembly mounted therein thatgenerates a profile ignition pickup (PIP) signal indicative ofcrankshaft position and engine RPM to said electronic control assembly(ECA); and an ignition module for receiving the spark output (SPOUT)signal from the electronic control assembly (ECA), said ignition moduleincluding a microprocessor for generating a control signal to anignition coil and switching ON and OFF the primary current therein and atemperature sensing circuit operative with the microprocessor forreducing the duty cycle as applied to the control signal from theignition module to the ignition coil and reducing the heat generatedwhen a temperature threshold for the ignition module has been exceeded.2. An ignition system according to claim 1 and further comprising anarmature and shaft assembly mounted within the distributor, wherein saidignition module is mounted on the distributor.
 3. An ignition systemaccording to claim 1 wherein the microprocessor is operative forreducing the duty cycle from about 5% to about 15%.
 4. An ignitionsystem according to claim 1 wherein the temperature sensing circuitcomprises a temperature sensing resistor and reference diode forestablishing a temperature control signal to the microprocessor that islinear with temperature change in the ignition module.
 5. An ignitionsystem according to claim 1 wherein the ignition module furthercomprises a circuit for reducing vehicle voltage that is about 14 toabout 15 volts to about 5 volts for supplying power to themicroprocessor.
 6. An ignition system according to claim 1 wherein theignition module further comprises a signal input for receiving a profileignition pickup (PIP) signal from the Hall Effect stator assembly.
 7. Anignition system according to claim 6 wherein the microprocessor isoperative for comparing the spark output (SPOUT) signal with the profileignition pickup (PIP) signal to determine a timing interval forswitching ON and OFF the primary current within the ignition coil.
 8. Anignition system according to claim 6 wherein the microprocessor withinthe ignition module is operative for determining when an enginethreshold has been exceeded by processing engine operating parameters asdetermined by at least the spark output (SPOUT) signals and/or profileignition pickup (PIP) signals generated to the ignition module.
 9. Anignition system according to claim 1 wherein the microprocessor withinthe ignition module is operative for reducing the duty cycle after thetemperature threshold has been exceeded and when the engine RPM of thevehicle has dropped below a predetermined number.
 10. A distributor fora vehicle comprising: a distributor base having a Hall Effect statorassembly mounted therein and operative for generating a profile ignitionpickup (PIP) signal indicative of crankshaft position and engine RPM toan electronic control assembly (ECA) used on the vehicle; and anignition module that receives a spark output (SPOUT) signal from anelectronic control assembly (ECA) used on the vehicle, said ignitionmodule including a microprocessor for generating a control signal to anignition coil and switching ON and OFF the primary current therein, anda temperature sensing circuit operative with the microprocessor forreducing the duty cycle as applied to the control signal from theignition module to the ignition coil for reducing the generated heat bythe TFI module when a temperature threshold for the ignition module hasbeen exceeded.
 11. A distributor according to claim 10 and furthercomprising an armature and shaft assembly mounted within the distributorbase, wherein said ignition module is mounted on the distributor base.12. A distributor according to claim 10 wherein the microprocessor isoperative for reducing the duty cycle from about 5% to about 15%.
 13. Adistributor according to claim 10 wherein the temperature sensingcircuit comprises a temperature sensing resistor and reference diode forestablishing a temperature control signal to the microprocessor that islinear with temperature change in the ignition module.
 14. A distributoraccording to claim 10 wherein the ignition module further comprises acircuit for reducing vehicle voltage that is about 14 to about 15 voltsto about 5 volts for supplying power to the microprocessor.
 15. Adistributor according to claim 10 wherein the ignition module furthercomprises a signal input for receiving a profile ignition pickup (PIP)signal from the Hall Effect stator assembly.
 16. A distributor accordingto claim 15 wherein the microprocessor is operative for comparing thespark output (SPOUT) signal with the profile ignition pickup (PIP)signal within the ignition module to determine a timing interval forswitching ON and OFF the primary current within the ignition coil.
 17. Adistributor according to claim 16 wherein the microprocessor within theignition module is operative for determining when an engine thresholdhas been exceeded by processing engine operating parameters asdetermined by at least the spark output (SPOUT) signals and/or profileignition pickup (PIP) signals generated to the ignition module.
 18. Adistributor according to claim 10 wherein the microprocessor within theignition module is operative for reducing the duty cycle after thetemperature threshold has been exceeded and when the engine RPM of thevehicle has dropped below a predetermined number.
 19. An ignition moduleused for a vehicle ignition system comprising: a housing adapted formounting on a distributor; a thick film substrate contained within thehousing; a microprocessor mounted on the thick film substrate andoperative for receiving at least a spark output (SPOUT) signal from anelectronic control assembly (ECA) used on the vehicle and generating acontrol signal to an ignition coil and switching ON and OFF the primarycurrent therein; and a temperature sensing circuit operative with themicroprocessor such that the microprocessor reduces the duty cycle asapplied to the control signal generated to the ignition coil and reducesthe generated heat when a temperature threshold for the ignition modulehas been exceeded.
 20. An ignition module according to claim 19 whereinthe microprocessor is operative for reducing the duty cycle from about5% to about 15%.
 21. An ignition module according to claim 19 whereinthe temperature sensing circuit comprises a temperature sensing resistorand reference diode for establishing a temperature control signal to themicroprocessor that is linear with temperature change in the ignitionmodule.
 22. An ignition module according to claim 19 and furthercomprising a circuit for reducing vehicle voltage of that is 14 to about15 volts to about 5 volts for supplying power to the microprocessor. 23.An ignition module according to claim 19 and further comprising a signalinput for receiving a profile ignition pickup (PIP) signal from the HallEffect stator assembly.
 24. An ignition module according to claim 23wherein the microprocessor is operative for comparing the spark output(SPOUT) signal with the profile ignition pickup (PIP) signal within theTFI module to determine a timing interval for switching ON and OFF theprimary current within the ignition coil.
 25. An ignition moduleaccording to claim 23 wherein the microprocessor is operative fordetermining when an engine threshold has been exceeded by processingengine operating parameters as determined by at least the spark output(SPOUT) and/or profile ignition pickup (PIP) signals generated to theignition module.
 26. An ignition module according to claim 19 whereinthe microprocessor is operative for reducing the duty cycle after thetemperature threshold has been exceeded and when the engine RPM of thevehicle has dropped below a predetermined number.
 27. A method ofoperating an ignition system of a vehicle having an electronic enginecontrol (EEC) comprising the steps of: monitoring the temperature in anignition module mounted on a distributor having a Hall Effect statorassembly that generates a profile ignition pickup (PIP) signalindicative of crankshaft position and engine RPM to the electroniccontrol assembly (ECA), which produces a spark output (SPOUT) signal tothe ignition module, wherein the ignition module includes amicroprocessor for generating a control signal to the ignition coil andswitching ON and OFF the primary current therein; and reducing the dutycycle as applied to the control signal from the ignition module to theignition coil and reducing the heat generated by the ignition modulewhen a temperature threshold for the ignition TFI module has beenexceeded.
 28. A method according to claim 27 and further comprising thestep of reducing the duty cycle from about 5% to about 15%.
 29. A methodaccording to claim 27 and further comprising the step of transmittingthe profile ignition pickup (PIP) signal to the ignition module.
 30. Amethod according to claim 29 and further comprising the step ofcomparing the spark output (SPOUT) signal with the profile ignitionpickup (PIP) signal within the ignition module to determine a timinginterval for switching ON and OFF the primary current within theignition coil.
 31. A method according to claim 29 and further comprisingthe step of determining when the temperature threshold has been exceededby processing engine operating parameters as determined by at least thespark output (SPOUT) and/or profile ignition pickup (PIP) signalsgenerated to the ignition module.
 32. A method according to claim 27 andfurther comprising the step of reducing the duty cycle after thetemperature threshold has been exceeded and when the engine RPM of thevehicle has dropped below a predetermined number.
 33. A method accordingto claim 27 and further comprising the step of sensing temperaturewithin the ignition module for determining when the temperaturethreshold for the ignition module has been exceeded.
 34. A methodaccording to claim 27 and further comprising the step of sensing currentwithin a temperature sensing circuit for determining when if thetemperature threshold has been exceeded.
 35. A method according to claim34 wherein the temperature sensing circuit comprises a temperaturesensing resistor.
 36. A method according to claim 35 and furthercomprising the step of rectifying a signal that passes through thetemperature sensing resistor using a reference diode for establishing atemperature control signal to the microprocessor that is linear withtemperature change in the ignition module.
 37. A method of operating anignition system of a vehicle having an electronic engine control (EEC)comprising the steps of: monitoring the temperature of an ignitionmodule that receives a spark output (SPOUT) signal from an electroniccontrol assembly (ECA) and generates a control signal to an ignitioncoil for switching ON and OFF the primary current therein; and reducingthe duty cycle as applied to the control signal from the ignition moduleto the ignition coil and reducing the heat generated by the ignitionmodule when a temperature threshold for the ignition module has beenexceeded.
 38. A method according to claim 37 and further comprising thestep of generating the control signal from a microprocessor positionedwithin the ignition module.
 39. A method according to claim 37 andfurther comprising the step of generating a profile ignition pickup(PIP) signal indicative of a crankshaft position and engine RPM to theelectronic control assembly (ECA).
 40. A method according to claim 37and further comprising the step of mounting the ignition module on adistributor of the vehicle.
 41. A method according to claim 37 andfurther comprising the step of reducing the duty cycle from about 5% toabout 15%.
 42. A method according to claim 37 and further comprising thestep of transmitting a profile ignition pickup (PIP) signal to theignition module.
 43. A method according to claim 37 and furthercomprising the step of comparing the spark output (SPOUT) signal with aprofile ignition pickup (PIP) signal within the ignition module todetermine a timing interval for switching ON and OFF the primary currentwithin the ignition coil.
 44. A method according to claim 37 and furthercomprising the step of sensing temperature within the ignition modulefor determining when the temperature threshold for the ignition modulehas been exceeded.
 45. A method according to claim 37 and furthercomprising the step of sensing current within a temperature sensingcircuit for determining when the temperature threshold has beenexceeded.
 46. A method according to claim 45 wherein the temperaturesensing circuit comprises a temperature sensing resistor.
 47. A methodaccording to claim 46 and further comprising the step of rectifying asignal that passes through the temperature sensing resistor using areference diode for establishing a temperature control signal to themicroprocessor that is linear with temperature change in the ignitionmodule.